As is known, said conveying ducts are generally situated inside the engine compartment of the motor vehicles, where they extend in a winding progression so to not interfere with the other devices contained therein.
For this reason, the conveying ducts are generally composed of a succession of substantially rectilinear rubber tubes, which are connected with each other, watertight, by means of appropriate connection elements made of typically metallic, plastically deformable material which can be bent to make the elbows of the duct.
Said connection elements generally comprise an intermediate tube and two lateral connection sleeves, which are inserted on the end section of a respective rubber tube, and are subsequently plastically deformed so to be fixed to the same tube.
In the manufacturing of the conveying ducts, such plastic deformation is normally achieved by means of fixed operating machines which comprise a substantially annular support structure which bears a set of radial punches arranged around its central axis.
The conveying duct is made to axially slide inside said support structure, so to position each time the connection sleeves in an operating position, wherein they are surrounded by said radial punches.
Therefore, said punches are simultaneously operated and pressed on the connection sleeve, so to make overall a series of circumferential crimps on the sleeve which are pressed against the rubber tube, which firmly fix it to the latter.
In particular, to ensure the watertight seal of said fixing, the use of operating machines having at least eight radial punches has been shown to be necessary.
In the repairing of conveying ducts, such fixed operating machines cannot be effectively used since they do not permit operating directly on the conveying duct without removing it from the system.
Therefore, in this field, portable tools are normally used of small size, which can be easily manipulated by a user and are less costly.
Said portable tools are of clamp type, and comprise two jaws which are generally lunette-shaped and have facing concavities, which are mutually movable along a rectilinear direction, with mutual approaching and moving away motion between an open rest position and a closed work position.
Every single jaw bears a set of punches arranged radially with respect to the axis of the respective lunette, such that during the mutual approaching movement between the jaws—generally driven by a jack—said punches are pressed on the connection sleeve, realising the abovementioned circumferential crimps.
Said jaws are mutually connected by means of two lateral guide stems which define, with the same jaws, an encircling structure which surrounds the connection sleeve even when the tool is in rest position.
For this reason, the connection sleeve must necessarily be axially inserted inside said encircling structure; this requires that the conveying duct is removed beforehand from the related system, considerably increasing the work times and the operating difficulties.
Moreover, since the jaws are moved in a rectilinear direction, the punches are pressed on the connection sleeve with a deforming force whose radial component depends on the tilt of every single punch with respect to the aforesaid direction.
This fact, in addition to leading to the realisation of imperfect circumferential crimps, also limits the maximum number of punches which can be mounted on the tool, beyond which the more tilted punches would result totally ineffective.
For the known tools, such maximum limit is six punches, and is therefore generally insufficient for ensuring the watertight seal of the connection which is made between the connection sleeve and the rubber tube inserted in it.
The present invention moreover regards a device for the actuation of work tools of portable type, i.e. which can be easily handled and transported by the user during their use.
More in particular, the invention regards a device intended to be associated with any one portable work tool which can be operated by means of a hydraulic jack.
As is known, the portable work tools commonly comprise movable operating members, which are connected by means of an appropriate kinematic system which permits them to be mutually moved, so to carry out the operation for which the related tool is assigned.
One such example is provided by the already mentioned clinching tools which are normally employed for realising a connection between two flexible tubes.
In fact, said clinching tools generally comprise a plurality of punches adapted to be arranged around a connection boss placed at the end of said tubes, and a kinematic system adapted to press said punches on the connection boss itself, to deform it and firmly fix it to the tubes.
The kinematic system which connects the operating members of the known clinching tools is normally operated by a hydraulic jack, whose operating fluid, typically oil, is contained within a small tank which is firmly associated with the body of the jack itself; the oil is pushed in the compression chamber between the cylinder and piston by a manual volumetric pump.
Said volumetric pump commonly comprises a plunger sliding with alternating motion inside a cavity made in the jack body, so to define a work chamber communicating with the suction with the tank and with the delivery with the compression chamber.
Normally the plunger projects outside the jack body, and is mechanically coupled with a manual driving lever which permits an operator to movably engage it.
To transmit the operating members the correct force which permits the work tool to effectively realise the operation for which it is assigned, it is not unusual that even very high pressure values must be reached in the compression chamber of the hydraulic jack.
For this reason, it is necessary that the operator subjects the plunger to numerous back and forth strokes, with an increasingly elevated stress as the pressure in the compression chamber increases.
Therefore, one particularly noted drawback of the known work tools lies in the fact that their use is generally very slow and tiring for the operator.